My 89 has been having overheating problems for about the past 6 months, i've taken it into chevy and they said they couldnt find anything wrong and that my secondary fan does not kick on until 230f. well this passed week my car has heated up to about 260 and this morning it got to 280 before i caught it and was able to pull over.

im wondering if anyone else has experienced this problem with there C4s and if yall have any troubleshooting ideas to keep this from happening again. THANKS!!!

Devon

 

Almost everyone has a similar story.

Clean the void between the radiator and the condensor. The car is a street vacuum. If the dealer said they did it, check it. I had someone tell me they did it, and lied about it. I ended up pulling a basket full of debris out of there.

Make sure your egr is working. The egr not only is for emissions, but it "cools" the combustion when the engine is hot.

Make sure the car is tuned properly.

Consider a higher capacity radiator. DeWitts are highly praised.

That's a start.

 

okay so I'll deff try vacuuming out that gap i did it a few months ago but im living on a dirt road for a couple months so it wouldnt suprise me if its already gone to hell.

replaced the egr about 6 mo's ago because of the overheating issues.

I'm still kinda learning about these cars how much does tuning affect my temperature, would you advise me to do that before i look into new radiators??

Thanks again!!!

 

is this the first time it has reached 260? if not before this what temps were you seeing. The reason I ask is it sounds like "this weekend" was totaly different then what you normaly see.

 

I suggest tune, but it's not a major factor. And I'm not an expert, but it's worth checking.

 

yeah normally im able to catch it at like 250 and i shut her down for like thirty seconds and the temp drops back down to the 220s i turn her on the coolant starts pumping again and it drops to around 210 and were good.

like i said earlier this week it hit the 260's before i caught it and then this morning it got all the way to 280 and i couldnt get it to drop back down as quickly as normal, it took about 30 mins to get to the 230's and every time i turned my car back on it would heat immediately back up into the 40's or 50's. until i finally got it parked for class.

 

yeah itll prolly be a littlllle cheaper then a radiator too!

 

are you running down the road and seeing these temp or are you in stop and go traffic? if in stop and go traffic are you sure your fans are coming on??

 

sure about the fans and oddly enough i am moving but usually at high speeds with high rpms..... like this morning when i was late for class.....

 

Sounds like a coolant flow issue i.e a restriction.

 

I run hot in stop n go also , fans kick on @ 250 i wish there was a way to hook up a manual fan switch....or can I??

 

Vacuuming won't work. You need to remove the radiator, sit down with a six pack of beer, a bucket of soapy water and a fin straightener and go to town. You'll be amazed at what your vacuum couldn't get to. When I did this on my old 84, my average temp dropped 10 degrees.

1 wal-mart bag = 30% loss in cooling capacity. And as Relic noted, these cars are road vacuums. They inhale just about everything from the road, and it becomes lodged in front of the radiator. Removing it periodically is the ONLY way to get it out. In fact, while it's out, run it over to a good radiator shop and have them flush it to get all the debris out, and pressure test it too.

Once that's done and reinstalled, pressure test the system and check for flow. Check for thermostat operation, belt tension on the water pump, etc. There really isn't much to the cooling system.

You do NOT need a bigger radiator if everything is working right.....the factory one will cool the car just fine. I live in a very hot climate, and my car runs about 195 in moderate traffic, 205 in heavy. Yours should too.

 

Oh...almost forgot....if the overheating is only happening at high speed / RPM, check for a hose collapsing. If your uncertain about when the hoses were last replaced, go ahead and replace them. If they get soft enough, the suction can cause the lower hose to collapse, and it will produce what you're talking about.

 

Agree with the dog. You may also have a stat that is sticking. Id throw a new one in and make sure your full of cooleant.

 

analog gauge or digital gauge reading 260

 

I'm having the same issue with my '89 right now. I suspect that my heater core has been leaking ever so slightly and pulling air into the system when cooling off. This creates an air bubble or air lock in upper parts of the engine that will keep coolant from passing. This might also keep the temps sensors dry so that they have erratic readings from air temps. I'm still proving my theory as I have little time to work on the car.

 

Pressure test the system. If it's bleeding somewhere, you'll know it soon.

 

...along with everything else but I didn't want to quote it all.

 

I wouldn't believe mine was plugged between the radiator and condensor. I flushed the area, looked between them with a light blew with an air hose. Realy felt the area was clean. Finally pulled the radiator and filled a 5 gal bucket with leaves wrapers etc. If i'm stuck in heavy trafic the temp gets to 225* the fan turns on and within seconds the temp is 200*. Pull the radiator you my find it an easy solution.

 

Replace the Thermostat.


I installed a toggle switch to my puller fan wiring.


You need to change your oil soon!

Seriously, change your THERMOSTAT, this same thing happened to my 85.